This invention relates to an easily openable package of photographic photosensitive materials which is very easily openable by hand and a method of producing the same.
Heretofore, several packaging materials having good openability are known for light-shielding bags for photographic photosensitive materials. A conventional easily openable packaging material for photographic photosensitive materials is composed of a light-shielding heat sealing film layer containing a lubricant, a light-shielding material and more than 50 wt. % of LDPE resin, an aluminum foil layer, on which an anchor coat layer is formed, laminated onto the light-shielding heat sealing film layer with a peeling strength of more than 400 g/15 mm width, and a heat-resistant flexible sheet layer having a heat resistance higher than the light-shielding heat sealing film layer by more than 5.degree. C. laminated onto the aluminum foil layer see U.S. Pat. No.4,708,896 . In the packaging material, since LDPE resin is used in order to ensure the tearability by hand, heat sealability and physical strength are inferior. When the packaging material was used for packaging a photographic photosensitive material having a weight of more than 500 g, pinholes and separation of the sealed portion tended to occur resulting in the loss of light-shielding, gas barrier and the like.
Another conventional easily openable packaging material is provided with a prescribed resin layer between two packaging material surfaces, and thereby, both packaging material surfaces are easy to separate (Japanese Utility Model KOKOKU No.60-7172). When the packaging material was used for packaging a photographic photosensitive material having a weight of more than 500 g, the sealed portion tended to separate due to the heat seal strength which is rendered small. Therefore, this packaging material is unsuitable for packaging photographic photosensitive materials.